Challenges to the effectiveness of next-generation sequencing in formalin-fixed paraffin-embedded tumor samples for non-small cell lung cancer.

INTRODUCTION: Next-generation sequencing (NGS) of Formalin-Fixed and Paraffin-Embedded (FFPE) specimens is routine in precision oncology practice. However, results are not always conclusive, and it is important to identify which factors may influence FFPE tumor sequencing success. MATERIALS AND METHODS: Here, we evaluated the influence of pre-analytical factors on 705 samples of non-small cell lung cancer specimens that underwent NGS testing. Factors such as tumor site, tumor cell percentage, fragment size, primary tumor or metastasis, presence of necrosis, DNA purity, DNA concentration, sample origin and year of testing. RESULTS: The overall NGS success rate was 84.9 % (n = 599). Bone site specimens had a very low success rate (42.1 %), differing from lung samples (79.8 %) (P < 0.05). Samples with tumor percentages <5 % (success rate of 44.4 %) represented 14.1 % of failed sequencings. Moreover, samples with tumor percentages >10 %-20 % (82 %) did not differ from those with >30 % (88.9 %) on sequencing outcomes (P = 0.086). Specimens that provided DNA concentrations >2.0 ng/uL, 1.0-2.0 ng/uL, 0.5-1.0 ng/uL and <0.5 ng/uL had success rates of 92 %, 77.1 %, 61.3 % and 20.4 %, respectively. Small fragments (≤0.2 cm2) had a success rate of 74.7 % and were more prevalent in the unsuccessful group (P < 0.05). CONCLUSIONS: Our results suggest that tumor percentage, fragment size, decalcified bone specimens, and DNA concentration are potential modifiers of NGS success rates. Interestingly, specimens with tumor percentages between 10 % and 20 % have the same sequencing outcome than specimens with >30 %. These results can strengthen the understanding of factors that lead to NGS success variability.

Silencing of the transcription factors Oct4, Sox2, Klf4, c-Myc or Nanog has different effect on teratoma growth.

Induced pluripotent stem cells (iPSC) have a great potential, but their clinical application depends on finding strategies to abolish their tumorigenic potential. The use of Oct4, Sox2, Klf4, c-Myc and Nanog to generate iPSC demonstrated the already known importance of these genes to maintain stemness. Therefore, the presence of these genes is responsible for iPSC-derived teratomas. Similar to iPSC, P19 teratocarcinoma cell line also has characteristics of embryonic carcinoma cells and the ability to differentiate into many cell types. We separately silenced the transcription factors Oct4, Sox2, Klf4, c-Myc and Nanog in P19 cells and measured the impact of this silencing in vivo. All silenced cells generated tumors when injected in immunosuppressed mice, but silencing of Oct4, Sox2 and Klf4 generated mainly teratomas with mesoderm tissue. Our results suggest that downregulation of these transcription factors is not enough to avoid the formation of teratomas, but their silencing affect their differentiation potential.

Autophagy and nuclear morphometry are associated with histopathologic features in esophageal squamous cell carcinoma.

Less than 15% of patients with esophageal squamous cell carcinoma (ESCC) survive 5 years after diagnosis. A better understanding of the biology of these tumors and the development of clinical biomarkers is needed. Autophagy is a physiological mechanism involved in the turnover of cellular components that plays a key role in cancer. This study evaluated the differential levels of three key regulators of autophagy (SQSTM1, MAP1LC3B, and BECN1) in patients with ESCC, associating autophagy with histopathologic features, including the grade of differentiation, mitotic rate, inflammation score, and the intensity of tumor-infiltrating lymphocytes. Nuclear morphometry of the tumor parenchyma was also assessed, associating it with autophagy and histopathology. All three markers significantly increased in patients with ESCC compared to the control group. Based on the mean expression of each protein in the control group, 57% of patients with ESCC had high levels of all three markers compared to control patients (14%). The most frequent profiles found in ESCC were BECNhigh/MAP1LC3high and BECNhigh/SQSTM1high. According to the TCGA database, we found that the main autophagy genes were upregulated in ESCC. Moreover, high levels of autophagy markers were associated with a poor prognosis. Considering nuclear morphometry, ESCC samples showed a significant reduction in nuclear area, which was strongly negatively correlated with autophagy. Finally, the percentage of normal nuclei was associated with tumor differentiation, while poorly differentiated tumors showed lower SQSTM1 levels. ESCC progression may involve increased autophagy and changes in nuclear structure, associated with clinically relevant histopathological features. KEY MESSAGES: Autophagy markers are co-increased in primary ESCC. Autophagy negatively correlates with nuclear morphometry in ESCC parenchyma. Autophagy and nuclear morphometry are associated with histopathological features. Autophagy is increased in ESCC-TCGA database and associated with poor prognosis.

Incipient Parallel Evolution of SARS-CoV-2 Deltacron Variant in South Brazil.

With the coexistence of multiple lineages and increased international travel, recombination and gene flow are likely to become increasingly important in the adaptive evolution of SARS-CoV-2. These processes could result in genetic introgression and the incipient parallel evolution of multiple recombinant lineages. However, identifying recombinant lineages is challenging, and the true extent of recombinant evolution in SARS-CoV-2 may be underestimated. This study describes the first SARS-CoV-2 Deltacron recombinant case identified in Brazil. We demonstrate that the recombination breakpoint is at the beginning of the Spike gene. The 5' genome portion (circa 22 kb) resembles the AY.101 (Delta), and the 3' genome portion (circa 8 kb nucleotides) is most similar to the BA.1.1 (Omicron). Furthermore, evolutionary genomic analyses indicate that the new strain emerged after a single recombination event between lineages of diverse geographical locations in December 2021 in South Brazil. This Deltacron, AYBA-RS, is one of the dozens of recombinants described in 2022. The submission of only four sequences in the GISAID database suggests that this lineage had a minor epidemiological impact. However, the recent emergence of this and other Deltacron recombinant lineages (XD, XF, and XS) suggests that gene flow and recombination may play an increasingly important role in the COVID-19 pandemic. We explain the evolutionary and population genetic theory that supports this assertion, concluding that this stresses the need for continued genomic surveillance. This monitoring is vital for countries where multiple variants are present, as well as for countries that receive significant inbound international travel.

Evaluation of EDTA and nitric acid solutions for decalcification of joints in AG/WT, BALB/c, C57, DBA1/J mice, and in Wistar rats.

Decalcification of mineralized samples for microscopic analysis involves competing factors including decalcification time, preservation of tissue integrity and cost. We investigated the utility of different decalcification solutions for studying joints in AG/WT, BALB/c, C57, DBA1/J mice and Wistar rats. The hind paws of the rodents were removed and fixed with 10% buffered formalin. Specimens were divided randomly into three groups for demineralization: 10% nitric acid, 12.5% EDTA at room temperature and 12.5% EDTA at 35 °C with shaking. Sections of joints were stained with hematoxylin and eosin (H & E). We evaluated decalcification time and expense, ease of cutting sections, preservation of nuclear basophilia and intranuclear detail, and intensity of eosin staining. The 10% nitric acid solution produced the most rapid decalcification for the mice, but not the rats. The 12.5% EDTA solution at 35 °C with shaking did not decrease decalcification time. Effects on microtomy were variable as were the effects on H & E staining. The EDTA solution provided the best basophilia and intranuclear detail for the mice. For rats, only 12.5% EDTA at 35 °C with shaking produced good preservation. Preservation of nuclear basophilia and intranuclear detail for rats was best with 10% nitric acid and EDTA 35 °C. For mice, 10% nitric acid failed to preserve nuclear basophilia and intranuclear detail. For intensity of eosin staining, EDTA at room temperature and EDTA 35 °C was best for both mice and rats. Sections also exhibited good H & E staining in most samples decalcified with 10% nitric acid. Although we found considerable variation among groups of animals, we found less variation among the different mouse strains than between mice and Wistar rats.

Mongolian Gerbils as a Model for the Study of Cholesteatoma: Otoendoscopic as a Diagnostic Tool.

Introduction Cholesteatoma is a disease with significant clinical impact but is incompletely understood. The challenge of performing studies with long-term follow-up in humans is a factor that has restricted the advance of knowledge in this field. Thus, the use of animal models is highly pertinent, and the Mongolian gerbil model has emerged as one of the most useful. Objective The present study aims to evaluate, through serial otoendoscopies, the development and characteristics of pars flaccida retraction pocket and cholesteatoma in Mongolian gerbils after obliteration of the eustachian tube and compare it with the control group. Methods Forty Mongolian gerbils were divided into two groups of 20 animals each. In the intervention group, the animals were followed with serial otoendoscopies after eustachian tube obliteration. In the control group, the animals were only followed through serial otoendoscopies. Results At the end of the 16-week follow-up, cholesteatoma was present in 13 of 38 (34.2%) ears in the intervention group, and in 7 of 34 (20.6%) in the control group ( p = 0.197). When we considered cholesteatoma and its potential precursor, pars flaccida retraction pocket, in a combined way, we verified it in 23 of 38 (60.8%) in the intervention group and in 11 of 34 (32.3%) in the control group ( p = 0.016). Conclusions Over the 16 weeks of follow-up, serial otoendoscopies enabled us to evaluate the formation and development of pars flaccida retraction pockets and cholesteatomas in Mongolian gerbils and proved to be an excellent diagnostic tool.

A qualitative study exploring the process of postmortem brain tissue donation after suicide.

Access to postmortem brain tissue can be valuable in refining knowledge on the pathophysiology and genetics of neuropsychiatric disorders. Obtaining postmortem consent for the donation after death by suicide can be difficult, as families may be overwhelmed by a violent and unexpected death. Examining the process of brain donation can inform on how the request can best be conducted. This is a qualitative study with in-depth interviews with forty-one people that were asked to consider brain donation-32 who had consented to donation and 9 who refused it. Data collection and analyses were carried out according to grounded theory. Five key themes emerged from data analysis: the context of the families, the invitation to talk to the research team, the experience with the request protocol, the participants' assessment of the experience, and their participation in the study as an opportunity to heal. The participants indicated that a brain donation request that is respectful and tactful can be made without adding to the family distress brought on by suicide and pondering brain donation was seen as an opportunity to transform the meaning of the death and invest it with a modicum of solace for being able to contribute to research.

Neuronal Death, Glial Reactivity, Microglia Activation, Oxidative Stress and Bioenergetics Impairment Caused by Intracerebroventricular Administration of D-2-hydroxyglutaric Acid to Neonatal Rats.

D-2-hydroxyglutaric acid (D-2-HG) accumulates and is the biochemical hallmark of D-2-hydroxyglutaric acidurias (D-2-HGA) types I and II, which comprehend two inherited neurometabolic diseases with severe cerebral abnormalities. Since the pathogenesis of these diseases is poorly established, we tested whether D-2-HG could be neurotoxic to neonatal rats. D-2-HG intracerebroventricular administration caused marked vacuolation in cerebral cortex and striatum. In addition, glial fibrillary acidic protein (GFAP), S-100 calcium binding protein B (S100B) and ionized calcium-binding adapter molecule 1 (Iba-1) staining was increased in both brain structures, suggesting glial reactivity and microglial activation. D-2-HG also provoked a reduction of NeuN-positive cells in cerebral cortex, signaling neuronal death. Considering that disturbances in redox homeostasis and energy metabolism may be involved in neuronal damage and glial reactivity, we assessed whether D-2-HG could induce oxidative stress and bioenergetics impairment. D-2-HG treatment significantly augmented reactive oxygen and nitrogen species generation, provoked lipid peroxidation and protein oxidative damage, diminished glutathione concentrations and augmented superoxide dismutase and catalase activities in cerebral cortex. Increased reactive oxygen species generation, lipoperoxidation and protein oxidation were also found in striatum. Furthermore, the antagonist of NMDA glutamate receptor MK-801 and the antioxidant melatonin were able to prevent most of D-2-HG-induced pro-oxidant effects, implying the participation of these receptors in D-2-HG-elicited oxidative damage. Our results also demonstrated that D-2-HG markedly reduced the respiratory chain complex IV and creatine kinase activities. It is presumed that these deleterious pathomechanisms caused by D-2-HGA may be involved in the brain abnormalities characteristic of early-infantile onset D-2-HGA.

Acute necrotizing eosinophilic myocarditis possibly triggered by an antimigraine drug as an uncommon cause of acute heart failure: a case report.

BACKGROUND: Epigastric or chest pain with an abnormal electrocardiogram (ECG) in a young, otherwise healthy patient should trigger an investigation to rule out myocarditis. The myocarditis covers a wide spectrum of severity. The search for the aetiologic factor could be definitive for the success of therapy. CASE SUMMARY: A previously healthy 29-year-old woman presented to the Emergency Room with epigastric pain, eosinophilia, and an abnormal ECG. A thorough evaluation including cardiac magnetic resonance and endomyocardial biopsy was undertaken. A diagnosis of acute necrotizing eosinophilic myocarditis was made. DISCUSSION: The case is particularly unique for its suspected predisposing trigger: an antimigraine drug. A possible systemic hypersensitivity reaction, reflected by the occurrence of concomitant severe serum eosinophilia, acute myocarditis, and central nervous system vasculitis, was successfully treated with steroids, further supporting the diagnosis.

The relationship between vascular endothelial growth factor and histological grade in intracranial meningioma.

BACKGROUND: Meningioma is the most common benign intracranial neoplasm, accounting for 30% of all primary brain tumors. In 90% of cases, meningiomas are benign. Several aspects of molecular biology, including potential biomarkers, have been studied in attempts to better understand the natural history of meningiomas. Vascular endothelial growth factor (VEGF) is a biomarker responsible for inducing physiological and pathological angiogenesis. VEGF expression has been investigated as a potential predictor of several tumor aspects, including growth rate, recurrence rate, brain tissue invasion, peritumoral edema and surgical prognosis, and also as a marker of histological grade. However, there is no consensus in the literature with respect to the association between this biological factor and meningioma. We digitally analyzed immunohistochemical images using ImageJ software with the aim of correlating VEGF expression with tumor histology. METHODS: Tissue samples from patients presenting with meningioma who had undergone surgical removal between 2007 and 2016 at the Hospital de Clínicas de Porto Alegre (HCPA), in Southern Brazil, were analyzed to identify possible immunohistochemical associations between VEGF and histological grade and subtype. RESULTS: Seventy-six patients were included; 82% were female, mean age was 59.9 years (range: 18-91). No statistically significant associations were found between VEGF expression and histological grade or subtype (P = 0.310). CONCLUSION: Our findings suggest that VEGF is frequently present in meningiomas regardless of histological grade and should not be used as a marker of severity or histological grade.

Survival and prognostic factors in childhood medulloblastoma: A Brazilian single center experience from 1995 to 2016.

BACKGROUND: Medulloblastoma is the most common malignant brain tumor in the pediatric population. Despite prognosis improvement in the past two decades, one-third of the patients still remain incurable. New evidence suggests that medulloblastoma comprises four distinct entities; therefore, treatment de-escalation is required. The aim of this article is to evaluate epidemiological data from patients treated at our institution. The primary objective is to analyze overall survival (OS) and event-free survival (EFS) and the secondary objective is to identify prognostic factor from this cohort. METHODS: We retrospectively analyzed 69 patients who underwent surgical resection for medulloblastoma among 423 children from the tumor registry data bank of Santo Antônio Children's Hospital from 1995 to 2016. Kaplan-Meier method and Cox regression analysis were used to identify OS, EFS, and prognostic factors. RESULTS: The 5-year OS and EFS rates found were 44.5% and 36.4%, respectively. The extent of resection and radiotherapy as adjuvant treatments was positively correlated to outcome while metastatic disease at diagnosis was negatively related to OS. Age younger than 3 years old did not have a worse outcome in our cohort. CONCLUSION: Similar results to population-based studies were found, but we still face difficulties due to living in a developing country. In the near future, we look forward to new diagnostic techniques that will enable us to classify medulloblastomas according to molecular subgroups.

Xanthogranulomatous colloid cyst: Radiologic- pathologic correlation and diagnostic difficulties.

BACKGROUND: Despite colloid cyst in the third ventricle is a very usual cause of hydrocephalus, its xanthogranulomatous variant is rare. The most important differential diagnosis is the third ventricular craniopharyngioma. To the best of the authors' knowledge, there have been few cases of xanthogranulomatous variant colloid cysts reported in the English literature. CASE DESCRIPTION: A 77-year-old white woman presented with headaches, memory loss, and abnormal gait for the past 4 months. Magnetic resonance imaging revealed a solid cystic lesion measuring 3.0 cm×2.8 cm×2.9 cm located inside the anterior portion of the third ventricle causing obstructive hydrocephalus. The posterior portion of the lesion was predominantly solid and hypointense on T2 and T1, with areas of post- contrast enhancement, and the anterior portion was predominantly cystic with both hyper- and hypointense areas on T1 and T2, with no suppression on fluid-attenuated inversion recovery and no restriction to diffusion. The patient underwent a left frontal craniotomy with pterional approach, and the lesion was removed microsurgically. CONCLUSION: Xanthogranulomatous reaction is rarely described in colloid cysts, which happens as a response to desquamation of epithelial lining, subsequent lipid accumulation, and as tissue inflammatory response to intracystic hemorrhage. Microsurgical resection is the treatment of choice. As compared to the plain colloid cyst, these lesions are difficult to fully excise as the inflammatory reaction to the xanthomatous material leads to adhesions to adjacent structures; therefore, the aspiration of cystic contents without spillage is advisable to achieve maximal resection of cyst walls.

Acute lysine overload provokes marked striatum injury involving oxidative stress signaling pathways in glutaryl-CoA dehydrogenase deficient mice.

Glutaric acidemia type I (GA I) is a neurometabolic disorder of lysine (Lys) catabolism caused by glutaryl-CoA dehydrogenase (GCDH) deficiency. Patients are susceptible to develop acute striatum degeneration during catabolic stress situations whose underlying mechanisms are not fully established. Thus, in the present work we investigated the effects of a single intrastriatal Lys administration (1.5-4 µmol) to 30-day-old wild type (WT) and GCDH deficient (Gcdh-/-) mice on brain morphology, neuronal injury, astrocyte reactivity and myelin structure, as well as signaling pathways of redox homeostasis. We observed a marked vacuolation/edema in striatum and at higher doses also in cerebral cortex of Gcdh-/-, but not of WT mice. Lys also provoked a reduction of NeuN and synaptophysin, as well as an increase of astrocytic GFAP, in the striatum of Gcdh-/- mice, indicating neuronal loss and astrocyte reactivity. Furthermore, we verified an increase of Nrf2 and NF-κB expression in the nuclear fraction, and a decrease of heme oxygenase-1 (HO-1) content in the striatum of Lys-injected Gcdh-/- mice, implying disruption of redox homeostasis. Finally, it was found that Lys provoked alterations of myelin structure reflected by decreased myelin basic protein (MBP) in the cerebral cortex of Gcdh-/- mice. Taken together, the present data demonstrate neuronal loss, gliosis, altered redox homeostasis and demyelination caused by acute Lys overload in brain of Gcdh-/- mice, supporting the hypothesis that increased brain concentrations of glutaric and 3-hydroxyglutaric acids formed from Lys may be responsible for the acute brain degeneration observed in GA I patients during episodes of metabolic decompensation.

Vitamin D supplementation ameliorates arthritis but does not alleviates renal injury in pristane-induced lupus model.

Systemic lupus erythematosus (SLE) is a multifactorial and autoimmune inflammatory disease with pleomorphic clinical manifestations involving different organs and tissues. The study of different murine models has provided a better understanding of these autoimmune phenomena. Pristane-induced lupus represents a suitable model to study factors that could influence the induction and/or progression of SLE, including genetic factors. The objective of the present study was to evaluate the development and evolution of SLE after vitamin D supplementation in PIL model. Here, we evaluated the effects of vitamin D supplementation in model of pristane-induced SLE in female BALB/c mice. The animals were randomly divided into three groups: control group (CO), pristane-induced lupus group (PIL) and pristane-induced lupus group plus vitamin D (VD). Lupus was induced in PIL and VD groups using pristane. PIL group showed arthritis and kidney injury, characterized by increased proteinuria, glomerular mesangial expansion and inflammation. Moreover, PIL model showed increased levels of IL-6, TNF-α and IFN-γ in serum. We observed that treatment with vitamin D improved arthritis through reduced of incidence and arthritis clinical score and edema, but does not influenced renal injury. Treatment with vitamin D was not able to reduce proteinuria levels, decrease mesangial hypercellularity or IgG and IgM deposition in the kidney. Vitamin D supplementation did not alter IL-6, TNF-α, IL-2 and IL-4, but reduce IFN-γ. These results support that the role of vitamin D may be different depending on acting site, what could explain different responses according clinical phenotype. Therefore, further investigations of vitamin D are needed to explore the supplement dosage, timing, and the molecular basis in SLE.

Experimental Evidence that In Vivo Intracerebral Administration of L-2-Hydroxyglutaric Acid to Neonatal Rats Provokes Disruption of Redox Status and Histopathological Abnormalities in the Brain.

Tissue accumulation of L-2-hydroxyglutaric acid (L-2-HG) is the biochemical hallmark of L-2-hydroxyglutaric aciduria (L-2-HGA), a rare neurometabolic inherited disease characterized by neurological symptoms and brain white matter abnormalities whose pathogenesis is not yet well established. L-2-HG was intracerebrally administered to rat pups at postnatal day 1 (P1) to induce a rise of L-2-HG levels in the central nervous system (CNS). Thereafter, we investigated whether L-2-HG in vivo administration could disturb redox homeostasis and induce brain histopathological alterations in the cerebral cortex and striatum of neonatal rats. L-2-HG markedly induced the generation of reactive oxygen species (increase of 2',7'-dichloroflurescein-DCFH-oxidation), lipid peroxidation (increase of malondialdehyde concentrations), and protein oxidation (increase of carbonyl formation and decrease of sulfhydryl content), besides decreasing the antioxidant defenses (reduced glutathione-GSH) and sulfhydryl content in the cerebral cortex. Alterations of the activities of various antioxidant enzymes were also observed in the cerebral cortex and striatum following L-2-HG administration. Furthermore, L-2-HG-induced lipid peroxidation and GSH decrease in the cerebral cortex were prevented by the antioxidant melatonin and by the classical antagonist of NMDA glutamate receptor MK-801, suggesting the involvement of reactive species and of overstimulation of NMDA receptor in these effects. Finally, L-2-HG provoked significant vacuolation and edema particularly in the cerebral cortex with less intense alterations in the striatum that were possibly associated with the unbalanced redox homeostasis caused by this metabolite. Taken together, it is presumed that these pathomechanisms may underlie the neurological symptoms and brain abnormalities observed in the affected patients.

Induction of Neuroinflammatory Response and Histopathological Alterations Caused by Quinolinic Acid Administration in the Striatum of Glutaryl-CoA Dehydrogenase Deficient Mice.

Glutaric acidemia type I (GA I) is an inherited neurometabolic disorder caused by a severe deficiency of the mitochondrial glutaryl-CoA dehydrogenase (GCDH) activity. Patients usually present progressive cortical leukodystrophy and commonly develop acute bilateral striatal degeneration mainly during infections that markedly worse their prognosis. A role for quinolinic acid (QA), a key metabolite of the kynurenine pathway, which is activated during inflammatory processes, on the pathogenesis of the acute striatum degeneration occurring in GA I was proposed but so far has not yet been evaluated. Therefore, we investigated whether an acute intrastriatal administration of quinolinic acid (QA) could induce histopathological alterations in the striatum of 30-day-old wild-type (WT) and GCDH knockout (Gcdh-/-) mice. Striatum morphology was evaluated by hematoxylin and eosin, T lymphocyte presence (CD3), and glial activation (GFAP and S100ß) by immunohistochemistry and 3-nitrotyrosine (YNO2) by immunofluorescence. QA provoked extensive vacuolation, edema, and especially lymphocyte infiltration in the striatum of Gcdh-/-. QA also enhanced CD3 staining and the number of YNO2 positive cells in Gcdh-/- mice, relatively to WT, indicating T lymphocyte infiltration and nitrosative stress, respectively. QA-treated WT mice also showed an increase of GFAP and S100ß staining, which is indicative of reactive astrogliosis, whereas the levels of these astrocytic proteins were not changed in Gcdh-/- QA-injected mice. The present data indicate that QA significantly contributes to the histopathological changes observed in the striatum of Gcdh-/- mice.

Muscle wasting in osteoarthritis model induced by anterior cruciate ligament transection.

This study aimed to investigate the molecular pathways involved in muscle wasting in an animal model of osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT) in rats. Reduction of protein syntheses, increased proteolysis and impaired muscle regeneration are important pathways related to muscle wasting, and myogenin, MyoD, myostatin and MuRF-1 are some of their markers. Female Wistar rats were allocated into two groups: OA (submitted to the ACLT) and SHAM (submitted to surgery without ACLT). Nociception, spontaneous exploratory locomotion and body weight of animals were evaluated weekly. Twelve weeks after the disease induction, animals were euthanized, and the right knee joints were collected. Gastrocnemius muscle of the right hind paw were dissected and weighed. Gastrocnemius was used for evaluation of muscle atrophy and expression of IL-1ß, TNF-α, Pax7, myogenin, MyoD, myostatin and MuRF-1. Histopathology of the knee confirmed the development of the disease in animals of OA group. Gastrocnemius of OA animals showed a reduction of about 10% in area and an increased IL-1ß expression compared to animals of SHAM group. Expression of myostatin was increased in OA group, while myogenin expression was decreased. TNF-α, Pax7, MuRF-1 and MyoD expression was similar in both OA and SHAM groups. Nociception was significantly elevated in OA animals in the last two weeks of experimental period. Spontaneous exploratory locomotion, body weight and weight of gastrocnemius showed no difference between OA and SHAM groups. Gastrocnemius atrophy in OA induced by ACLT involves elevated expression of IL-1ß within the muscle, as well as increased expression of myostatin and decreased expression of myogenin. Therefore, muscle wasting may be linked to impaired muscle regeneration.

Mongolian Gerbils as a Model for the Study of Cholesteatoma: Otoendoscopic as a Diagnostic Tool

Abstract Introduction Cholesteatoma is a disease with significant clinical impact but is incompletely understood. The challenge of performing studies with long-term follow-up in humans is a factor that has restricted the advance of knowledge in this field. Thus, the use of animal models is highly pertinent, and the Mongolian gerbil model has emerged as one of the most useful. Objective The present study aims to evaluate, through serial otoendoscopies, the development and characteristics of pars flaccida retraction pocket and cholesteatoma in Mongolian gerbils after obliteration of the eustachian tube and compare it with the control group. Methods Forty Mongolian gerbils were divided into two groups of 20 animals each. In the intervention group, the animals were followed with serial otoendoscopies after eustachian tube obliteration. In the control group, the animals were only followed through serial otoendoscopies. Results At the end of the 16-week follow-up, cholesteatoma was present in 13 of 38 (34.2%) ears in the intervention group, and in 7 of 34 (20.6%) in the control group (p = 0.197). When we considered cholesteatoma and its potential precursor, pars flaccida retraction pocket, in a combined way, we verified it in 23 of 38 (60.8%) in the intervention group and in 11 of 34 (32.3%) in the control group (p = 0.016). Conclusions Over the 16 weeks of follow-up, serial otoendoscopies enabled us to evaluate the formation and development of pars flaccida retraction pockets and cholesteatomas in Mongolian gerbils and proved to be an excellent diagnostic tool.